1. Field of the Invention
The present invention relates to a method for producing an electrophotographic photosensitive member.
2. Description of the Related Art
Organic electrophotographic photosensitive members (hereinafter referred to as “electrophotographic photosensitive members”) have been increasingly used in the market as copiers and laser-beam printers have been spreading in recent years. An electrophotographic photosensitive member used in such equipment has an undercoat layer that contains metal oxide particles and a photosensitive layer on the undercoat layer.
The undercoat layer may contain an organic compound for some purposes such as stabilizing electrical properties and reducing failures in image quality. Japanese Patent Laid-Open No. 2006-221094 discloses a technology in which an undercoat layer contains an acceptor compound, such as an anthraquinone compound, in addition to metal oxide particles. The publication states that the acceptor compound preferably contains, in particular, a group that reacts with the metal oxide particles, adding that providing the undercoat layer with electron acceptability reduces ghosting.
On the other hand, Japanese Patent Laid-Open No. 58-017450 discloses a technology in which an undercoat layer contains a benzophenone compound, a known ultraviolet absorber. This technology reduces the damage to a charge transport material associated with ultraviolet radiation, thereby reducing the decline in electrical properties that occurs with repeated use of the electrophotographic photosensitive member.
Some of such organic compounds having a group that reacts with metal oxide particles, however, become more likely to absorb light from a semiconductor laser used as a light source upon interaction with the metal oxide particles. The oscillation wavelength of semiconductor lasers that are now commonly used as a light source ranges from 650 to 820 nm. When the reflectivity of the surface of the undercoat layer is low with respect to laser light in this wavelength range, the sensitivity of the electrophotographic photosensitive member may also be low.
It is therefore preferred to use a compound that remains unlikely to absorb light in the above wavelength range upon interaction with metal oxide particles. Even such a compound, however, can contain a colored impurity in addition to the main ingredient, depending on the process used to synthesize the compound. Such an impurity can reduce the reflectivity of the undercoat layer with respect to laser light and affect sensitivity as in the above case.